Safety paper



Patented Mar. 13, 19 28.

UNITED STATES- PATENT OFFICE.

WILLIAM R. ormnonrr, or nmca, NEW YORK, assreuon TO THE 'ronn 001mm, me, or nocn nsrna, NEW YORK, a coaroaa'rron on NEW YORK.

SAFETY PAPER.

and at the same time highly sensitive under the action of eradi'cators so as to afford a conspicuous and permanent discoloration upon treatment by them, as well as a paper capable of being manufactured on a commercial scale by simple, practical and economical methods. 7

To these and other ends the invention resides in certain improvements and combina- 20 tions of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

Safety papers have been made with a wide variety of chemical constituents intended to render them chemically sensitive when treat ed with ink eradicatin reagents for the pur: pose of indicating by t eresulting discoloration or stain that efforts have been made to alter matter written on the pa r. The use of instruments made from sue paper such, for example, as bank checks, su jects them ordinarily over a considerable period of time to widely varying conditions of light, temperature and moisture under which, however, the paper must remain stable and unchanged particularly if marked by sensitive 75 from which it will be seen that an oxidizing reagent such, for example, as chlorine converts two molecules of the 1,3-dimethyl ether of pyrogallol on the left of the equation into one modecule of coerulignone or 80 c'edriret, on the right of the equation.

The above chemical is readily applied to 8, 1925. Serial No. 1,811.

deep and conspicuous stain of such a nature as to be inevitably observed, as a w of attempted alteration. The majority of chemical ingredients heretofore employed for such purposes have been lacking in one or another of these essential requirements.

The present invention comprises the dis-- 'covery of a substance adapted to fill the above requirements in a highly satisfactory manner. This is the substance known as 1,3-dimethyl ether of pyrogallol or a salt thereof. This substance with its salts is easily obtainable commercially in a substan tially' colorless form, the latter being a further advantageous feature, as more fully explained hereafter. It is readily soluble in water or oil while some of its salts are solu ble in (water so that substantially colorless solutions in'these mediums can be produced of substantially any desired strength, suitable and convenient for use either to impregnate the material of the paper being manufactured or to apply in the form of an ink to the paper surface, or both.

The action of the ordinary eradicating fluids (bleaching or oxidizing) upon the 1,3-dimethyl ether of pyrogallol and its salts is to convert them into coerulignone or cedriret, which is conspicuously colored. This v reaction may be represented as follows:

0 the paper, for example, by the use of a solution of suitable strength, preferably embodied in the sizing. The strength of thethe paper as above described, this chemical may be compounded with a suitable water or oil medium to form an ink and so printed on the paper surface. Thus, the entire paper surface may be uniformly printed with a tihn of said ink or with any desired warning symbol or words. Additionally, the paper may be both impregnated with the chemical and also have its surface printed with an ink containing the same as above described, to thus afford a double form of protection.

The colorless character of the chemical is advantageous for the reason that it may be used with white paper or paper of any other color and because of its invisibility its presence cannot be detected beforehand. The safety paper made as described is thus generally suitable for bank checks and Substantially any other use for which safety paper may be desirable.

In addition to the above advantages, 1,3- dimethyl ether of pyrogallol and its salts are stable in character and not substantially affected by the action of light. temperature or moisture. but react sensitively and immediately with the usual eradicating fluids to develop a deep and conspicuousstain contrasting strongly with untreated surrounding portions of the paper to disclose attempted alterations in a striking manner. In View of the solubility in water and oil, the invention provides means for the production of paper and ink by a variety of commercially practical and economical methods.

While reference has been made in the above description to 1,3-dimethyl ether of pyrogallol or salts made therefrom as the preferred chemical form, it is appreciated that other derivatives and variants of 1,3-

dimethyl ether of pyrogallol may be employed which derive their effectiveness from the characteristic properties of 1,3-dimethyl ether of pyrogallol. Accordingly the reference in the following claims to a 1,3-di-' methyl ether of pyrogallol substance is in tended to be inclusive of all these materials having such properties described.

I claim as my invention:

1. A safety paper containing 1,3-dimethyl ether of pyrogallol.

2. A safety paper having its material impregnated with a substantially colorless 1,3- dimethyl ether of pyrogallol substance.

3. A safety paper impregnated with a sufficient quantity of a 1.3-dimethyl ether of pyrogallol substance to yield a conspicuous stain when treated with an eradicating reagent.

4. A safety paper impregnated with a 1,3- diniethyl ether of pyrogallol substance and having an ink applied to its surface containing the same in a suitable medium.

5. A safety paper impregnated with a sufficient quantity of a 1,3-dimethyl ether of pyrogallol substance in substantially colorless form to yield a conspicuous stain when treated with an oxidizing reagent and also having its surface printed with an ink comprising the same in a suitable medium.

6. A safety paper having its surface printed with an ink containing 1,3-dimethyl ether of pyrogallol.

7. A safety paper having its surface printed with a substantially colorless ink containing a sufficient quantity of a Lil-(limethyl ether of pyrogallol substance to yield a conspicuous stain when treated with an oxidizing reagent.

WILLIAM R. ORN'DORFF. 

